1. Field of the Invention
The invention relates to an overvoltage protection element for discharging transient overvoltages, with two electrodes, one disruptive discharge-spark gap which is active in air between the electrodes and a housing containing the electrodes, each electrode having a connecting leg and an arcing horn running at an acute angle to the connecting leg and the arcing horns of both electrodes, which are spaced from each other, forming the disruptive discharge-spark air gap.
2. Description of Related Art
Electric, in particular electronic, measuring, control, regulator, and switching circuits, also especially telecommunications devices and systems, are sensitive to transient overvoltages, as they can occur in particular due to atmospheric discharges, but also due to short circuits and switching operations in power supply systems. This sensitivity is increased to the degree that electronic components, in particular transistors and thyristors, are used; above all, increasingly used integrated circuits are endangered to a high degree by transient overvoltages.
Besides the overvoltage protection element on which the invention is based (see German Patent 37 16 997), i.e., one with a disruptive discharge-spark air gap, there are overvoltage protection elements with a flashover-spark gap in air in which, e.g., during sparkover, a creeping discharge occurs (see German Patents 27 18 188 and 31 01 354 and German Application DE 29 34 236 A1).
Overvoltage protection elements of the type to which the present invention is directed, i.e., those with a disruptive discharge-spark air gap, have, compared to overvoltage protection elements with a flashover-spark air gap, the advantage of higher surge withstanding strength, but the drawback of a higher, and also not particularly constant, sparkover voltage.
Various overvoltage protection elements have already been developed with a disruptive discharge-spark air gap that have been improved with respect to the sparkover voltage (see DE-A-41 41 681, DE-A-41 41 682 and DE-A-42 44 051).